As wireless communications evolve, wireless technology allows for increasing functionality and capabilities. One capability is the ability to hold Internet Protocol (IP) multimedia subsystem (IMS) sessions. IMS is an architectural framework for delivering IP-based multimedia services. A wireless transmit/receive unit (WTRU) may connect to an IMS through various access networks, including but not limited to networks based on technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE), Worldwide Interoperability for Microwave Access (WiMax), or Wireless Local Area Network (WLAN) technology. A WTRU may access the IMS through a packet-switched (PS) domain. Through the use of IMS Centralized Services (ICS), a WTRU may additionally access IMS services via a circuit-switched (CS) domain.
Further, through the use of IMS sessions a WTRU is capable of holding media sessions with a remote party. Examples of these media sessions include audio, video or text sessions. Multiple WTRUs may also participate in a collaborative media session or sessions with a remote party through use of IMS.